Given the reduced size of many consumer electronic devices, packaging systems are becoming increasingly important. For example, cellular telephones are becoming smaller and smaller to satisfy consumer's desires for portable lightweight telephones that are easy to carry. Such devices must still provide all the features and functions consumers require. For example, portable computer systems must provide input and output ports, a display, and a user input device. Furthermore, the progression to smaller and smaller consumer devices with advanced features is extending to Personal Digital Assistants (PDAs) and notebook computers
However, small consumer devices have problems that are typically not encountered by larger devices. For example, many small consumer devices are meant to be handheld, thereby making it easy for users to carry the devices and operate them at remote locations. These devices include user input devices, such as a touch pad, pen stylus and buttons to allow users to activate programs or input information.
In a typical computer system, various hardware devices may be provided with their own dedicated and non-shareable interrupt line that is used to activate their associated driver programs. However, this requires the computer system to have substantial interrupt resources. Furthermore, in a typical system, the interrupt resources are based on older architectures, referred to as “legacy” interrupts, which provide slow performance that can result in an unsatisfactory user experience with the device.
Another problem that exists affecting small handheld devices is that there are a limited number of buttons that can be accommodated by the device housing. Therefore, current handheld devices generally limit the types and numbers of functions that are available to a user via the buttons. For example, buttons may be used to activate application programs and make basic selections, however, these same buttons may not be used to process system level functions.
Another problem that exists affecting small handheld devices is that because they are small and designed to be carried by a user, it is easy for buttons to be accidentally depressed when handled. For example, a user may hold the device with one hand while inputting information with the other. The hand being used to hold the device may accidentally depress buttons on the device that activate other device functions. Thus, it is possible to inadvertently lose information or interrupt the operation of the device because of the accidental button press.
Therefore, it would be desirable to have a system to process button actuations in a small computer device that avoids the problems associated with conventional systems.